1. Field of the Invention
The present invention generally relates to the art of electronic digital computers, and more specifically to a method and implementation for intercepting and processing system calls to emulate a retrograde operating system.
2. Description of the Related Art
Operating systems for electronic digital computers are constantly improving and evolving. The UNIX.RTM. operating system, for example, has gone through a number of transformations, and is currently exists in a number of older and newer versions. The Solaris.RTM. X86 2.X operating system, a product of Sun Microsystems of Mountain View, Calif., evolved from the UNIX system.
The Common Object File Format (COFF) is an older type of executable binary program which runs on older versions of UNIX, including those from Interactive Systems Corporation (ISC) of Santa Monica, Calif., and Santa Cruz Operations (SCO) of Santa Cruz, Calif. Although the kernel of the Solaris operating system generally understands the COFF format, numerous incompatibilities have emerged including changes in system calls, arguments given to system calls, changes in signal numbers, changes in filenames, changes in the formats of files, etc. There are also incompatibilities between ISC and SCO COFF binaries.
It is desirable for a current operating system such as Solaris.RTM. X86 to be able to run retrograde user programs such as COFF binaries without modification to the programs. However, this has not been heretofore possible due to incompatibilities including those presented above.